A high resolution zone electrophoresis technique was combined with immunofixation electrophoresis and applied in studies of CSF proteins from normal subjects and patients with peripheral and central nervous system neuropathies. In one study, analysis of CSF samples from healthy volunteers demonstrated consistently the presence of a homogeneous protein band which was characterized unique to the CSF apparently originating from CNS tissues (1). In a second study an IgM was detected in the CSF of patients with polyneuropathy. An association between polyneuropathy and IgM paraproteinemia has been established. Determination of IgM in CSF can be of diagnostic value in these patients (2). In a third study the presence of oligoclonal bands was demonstrated in CSF samples from patients with late-postpoliomyelitis muscular atrophy. This information together with concurrent serological studies contributed to the concept that immunologic mechanisms play a role in the motor neuron disease occurring in these patients (3). In a fourth study a high incidence of monoclonal lambda light chains was detected in patients with Sjogren's Syndrome (SS) compared to a low incidence in patients with other autoimmune diseases. The finding of a monoclonal light chain in SS patients is important because a) it aids the differential diagnosis of these patients from other autoimmune diseases and b) it provides a critical link between autoimmunity and lymphoid malignancy (4).